Introducing mass movement hazard map in valley master plan to build back better
The implementation of the Sendai Framework recommendations for building back better in remote valleys of Nepal faces multiple challenges. The French NGO Architecture & Développement is piloting a project covering three districts in the Sindhupalchok district, 70 km North West of Kathmandu with the objective of providing safer homes to families who lost everything in 2015. Some villages were destroyed at 95% following the two earthquakes of 2015 while others were less affected. The usual dwellings are mostly traditional stone houses except some community or state facilities. Introducing earthquake resistant reinforced concrete for reconstruction is challenging as most of the houses are self-constructions with local materials.
The area has been affected by hundreds of mass movements, many of them being reactivations of pre-existing instabilities and the rest generated by the earthquake and aftershocks. There is no master plan in the valley to support the development of villages or infrastructures, nor is there any map of earthquake or ground instabilities, mass movements, floods or any other hazard.
Yet, building back better starts with constructing in the right place and avoiding reconstruction in risk sensitive areas. SIGNALERT produced a map of ground instabilities using satellite imagery. Several types of ground movements and several types of hazard levels have been displayed in two maps which can be introduced as component and backbone of a valley master plan. Fortunately the longstanding knowledge of the valley by its inhabitants is the base of a safe settlement and only two dozens of houses were found to be directly exposed to mass movement danger out of the several hundreds of the valley. The map is overlaid on a 1:50.000 topographic sheet but accuracy of interpretation is compatible with a use at 1:25.000 scale.
Support of self-reconstructions with a manual for more resistant traditional stone houses
Architecture & Développement supports the reconstruction of family houses. Families reconstruct generally as fast as possible on their property lot with material from the destroyed houses. The traditional style of stone buildings piled and assembled with wood, has to be significantly improved by the introduction of better building design and optimized work practices. The French Earthquake Engineering Association (AFPS) has released a few months ago a manual for post-earthquake rebuilding in Nepalese valleys. SIGNALERT contributed to the design and review of the manual based on former experiences in such manual production in France, Haiti and Djibouti. This guide initially published in English will be available in Nepalese in July 2016.
Architecture & Développement is also benchmarking and testing the AFPS guide, in its current houses reconstruction project. Such a guide needs to be introduced by referent people and put in the hand of former constructors, who have the real capacity of transmitting and making knew practices and knowledge adopted by local families. A feedback within a few months will result in some modification of the guide based on critics and suggestions by field practitioners.
Facilitating daily life with a smartphone app to report impact of mass movements
With the second monsoon following the earthquake coming within the next weeks, new ground instabilities will appear and many others will be reactivated in the Nepalese valleys.
Major ground movements are mapped and available as GIS layers for land use mapping and planning. But the most frequent and disrupting ground movements are small to very small instabilities, rocks and block falls along roads, tracks, pathways which can interrupt traffic for hours or days.
SIGNALERT crowdmapping smartphone application is used by local staff of Architecture & Développement to report all these small ground movements, which have an influence on local movements and daily activities of the villages’ residents.
The rock or block falls reports issued with the app by witnesses are shared by apps users and sent to a main web account. The SIGNALERT CONSULT account allows overview and analysis of all alerts and a view of dangers and disturbance evolutions.
The new testimonies sent with the app are structured and organized in order to provide both the physical intensity of the phenomenon and the damage and impact levels on people, environment, buildings, and infrastructures. The alert description is instantly visible in real time on the mapping interface by the people in charge of managing the project but also on the smartphone app. The mapping interface includes a tool for automatic detection of new events with real time notification by SMS and email to specified people. If an new event is passing a predefined threshold, in terms of number of alerts, level of intensity, level of impact in a defined duration, a notification is triggered and sent to the authorities.
The SIGNALERT CONSULT service (the mapping interface) includes a tool to send mass notifications (messages) to the app users located in the area of the event. The area covered by the project extends on large region north east of Kathmandu, including a part of Lang Tang valley.
Users of the app can report rock falls, floods on the area. The national, regional, district or VDC’s authorities can request the opening of an account to be granted the real time access to the interface and events alerts.
The app also has a paid version with additional personal security functions. Among them, the “I am safe” button transmits instantly to email and phones numbers defined in the app, a message giving your position, a text and a map. This version allows the user to choose places of interest and to be alerted in real time if an alert is issued in the vicinity of these points.
The SIGNALERT application is free and accessible on Googleplay and Appstore.
For more information:
[email protected] / +33145469315 or +33682689192
SIGNALERT
7 rue Danton, 92120 Montrouge, France
www.signalert.net